The present invention relates to a new and improved liquid-cooled electrical assembly.
Generally speaking, the liquid-cooled electrical assembly of the present development is of the type containing an arrangement for cooling at least one electric component under current. A liquid coolant flows into an inlet of a cooler and heated-up coolant is removed from the cooler through an outlet.
These types of assemblies have been known as state-of-the-art for a long time. Among these assemblies, electrical resistors deserve special mention because they have found such wide application. These resistors are generally available as wirewound resistors and have the main disadvantage that the heat produced by the current flowing through the resistance wire can only be relatively slowly carried away because of poor thermal contact between the resistance wire and the cooler. Furthermore, this thermal contact is made even poorer under ordinary operating conditions since parts of the resistance wire, for example, which were tightly wound around a central cooler in the current-free state can peel away from the cooler when it heats-up under current flow. This has the effect that some of the heat produced in the wire has to be conducted through an insulating layer of air which has formed between the wire and the cooler.
Furthermore, it is necessary to provide an insulating layer between a metallic cooler and the resistance wire. This layer is usually manufactured from pressed or sintered powder or a hardened or set casting resin. With present materials, a sufficient insulation only can be achieved with a relatively thick layer. This causes a further decrease in the thermal contact between the resistance wire and the cooler.